Densified halogenated dimethylhydantoins

ABSTRACT

Halogenated dimethylhydantoins are intimately mixed with calcium chloride and water and compressed to provide a densified particulate solid that is capable of withstanding the stresses of automatic packaging, conveying and handling.

This is a divisional of co-pending application Ser. No. 429,160 filed onSept. 30, 1982, now U.S. Pat. No. 4,532,330.

BACKGROUND OF THE INVENTION

A. Field of the Invention

The present invention discloses a novel method for the synthesis ofdihalogenated dimethylhydantoins intimately mixed with calcium chlorideand water to form densified particulate solids that withstand thestresses of automatic packaging, conveying, and handling.

B. Description of the Prior Art

Halogenated dimethylhydantoins containing bromine and/or chlorine havethe following structure: ##STR1## where X is bromine or chlorine. Suchhalogenated dimethylhydantoins are useful as bacteriocides in watertreatment processes because they provide a source of active halogen inlow concentrations. They are also highly efficient donors for effectingvarious organic syntheses.

The use of additives in agglomeration of compounds is well known in theliterature, with the number of additives used being as large as thenumber of compounds compacted or agglomerated. Calcium chloride has beenused as a curing agent in the cement industry, and the use of water asan adhesive in agglomeration is also known. However, calcium chlorideand water in intimate mixture with halogenated compounds has notheretofore been employed.

Halogenated dimethylhydantoins are produced as particulate solids, andfor certain uses it is desired to compact, agglomerate, extrude, orotherwise densify these particulate solids into tablets or othergeometrical shapes with sufficient strength to withstand automaticpackaging, conveying, and handling. When densified without additives,these compounds lack the strength to withstand such operations.Moreover, many compounds commonly used in the densification industry togive strength to agglomerates will chemically react or otherwiseinterfere with the desired uses of halogenated hydantoins.

U.S. Pat. No. 3,412,021 discloses the use of a variety of binders,principally polyvalent metal hydroxides, in preparing solid forms ofN-halogenated organic compounds. This patent, however, does not teachthe use of calcium chloride and water as densification or agglomerationagents in the preparation of solid halogenated dimethylhydantoins andthus does not render Applicant's methods or compositions unpatentable.

It is a primary object of this invention to obtain a method of producinghalogenated dimethylhydantoins having superior strength.

It is another object of this invention to create densified halogenateddimethylhydantoins which withstand automated packaging and handling,without interfering with other desired uses of the subject compounds.

SUMMARY OF THE INVENTION

The foregoing and other objects, advantages, and features may beobtained by intimately mixing halogenated hydantoins with calciumchloride and water. More particularly, calcium chloride and water whenmixed with halogenated dimethylhydantoins give densified shapes withsufficient strength to endure automated operations without reacting orotherwise interfering with the desired uses of these products.

Preferably, the halogenated dimethyl hydantoin is produced with calciumchloride formed in situ by the method of halogenating dimethyl hydantoinwith a first halogenation agent in the presence of water and source ofcalcium and hydroxide ions in order to form a monohalogenatedintermediate. Thereafter, the monohalogenated intermediate ishalogenated with a second halogenation agent in the presence of waterand a source of calcium and hydroxide ions, at least one of the firstand second halogenation agents including a source of chlorine. Thedihalogenated hydantoin thereby formed is separated from the reactionmixture without washing, and after densification contain calciumchloride and water, preferably at the level of about 2 to 6% and 1 to 5%respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, it has been discovered thatwhen the calcium chloride and water are mixed with the halogenated(i.e., bromine and/or chlorine-containing) dimethylhydantoins, thematerial can be compacted, agglomerated, extruded, or otherwisedensified into shapes with sufficient strength to withstand mechanicaland automated packaging and handling operations. Preferably, calciumchloride is provided in intimate mixture by its concurrent production insitu with the halogenated dimethylhydantoins. It is believed that thesuperior crush strength of the densified solid is due to the intimatelymixed nature of the solids and water.

The proces of this invention is employed in the preparation of densifieddihalogenated dimethylhydantoins, especiallybromochlorodimethylhydantoin, dibromodimethylhydantoin, anddichlorodimethylhydantoin. These materials are prepared by the reactionof dimethylhydantoin, and the corresponding source of halogen in water.The halogenation step is carried out in the presence of base toneutralize the acid formed in the halogenation step. Although almost anyinorganic source of --OH will do, sodium hydroxide, potassium hydroxide,and calcium hydroxide can be used. The inorganic source of --OH and thehalogenating agent are added concurrently at such a rate that the pH ismaintained in the range of about 6.8-7.0 and the temperature ismaintained at about 25° centigrade.

When the base used in the halogenation steps is sodium hydroxide orpotassium hydroxide, at the end of the halogenation step, the product istypically washed and dried leaving the dihalogenated dimethylhydantoinas a dry solid. In order to prepare the particulate solid in a formsuitable for densification, calcium chloride and water are added to thedried dihalogenated dimethylhydantoin and mechanically mixed with thesolid. The product dihalogenated dimethylhydantoin intimately mixed withcalcium chloride and water is now suitable for extrusion or forcompression into a desired shape.

Preferably the calcium chloride is prepared concurrently with thedihalogenated dimethylhydantoins by employing calcium hydroxide as thebase. After the halogenation step, if the dihalogenateddimethylhydantoin is filtered and not washed, the bi-product calciumchloride contained in the mother liquor is retained intimately mixed inthe product. After the majority of the mother liquor is removed byfiltration of the product, the wet solids may be then densified into thedesired shapes or extruded.

The amount of calcium chloride and water is desirably controlled so thatthe densified product consists of about 1-5% water by weight and about2-6% calcium chloride by weight.

When the halogenated dimethylhydantoins are prepared, washed and driedand then calcium chloride and water is added and mechanically mixed withthe solids, the densified solids prepared therefrom have exhibitedhigher crush strengths than the densification product formed from thepure halogenated dimethylhydantoin. The extent to which the halogenateddimethylhydantoins possess greater crush strengths when mechanicallymixed with calcium chloride and water depends on the efficiency and thelength of the mechanical mixing.

Generally, stoichiometric or slight excess amounts of the halogenationagents are employed, with the amount of base being that required toachieve a very slightly acidic pH.

In the preferred process water and dimethylhydantoin are added to thereactor, the water being in a four to five fold ratio by weight. Bromine(one-half mole per mole of dimethylhydantoin) and an aqueous slurry ofcalcium hydroxide (one-fourth mole per mole of dimethylhydantoin) areadded simultaneously at a rate that the temperature is controlled atabout 25° C. and the pH is controlled at about 6.8-7.0. After thebromine addition is completed, chlorine (one and one-half moles per moleof dimethylhydantoin) and calcium hydroxide (three-fourths mole per moleof dimethylhydantoin) were added at a rate to again control the pH atabout 6.8-7.0 and the temperature at about 25° C. The chlorine firstliberates bromine from the by-product calcium bromide and thereafterchlorine reacts with bromo dimethylhydantion.

At the end of the second halogenation step the resultant slurry ofsolids is filtered to remove the majority of the mother liquor, theby-product calcium chloride is thus retained in intimate mixture withthe solid product. This product, which comprises1-bromo-3-chloro-5,5-dimethylhydantoin and1-chloro-3-bromo-5,5-dimethylhydantoin, intimately mixed with calciumchloride and water is then densified into tablet shapes or extrusions,and dried to the desired proportion of water and calcium chloride.

Solids prepared from the dihalogenated dimethylhydantoins wherein thesource of the calcium chloride and water is the reaction mother liquorhave exhibited the highest crush strengths. It appears that the superiorcrush strengths of the densified solid by either method is due to theintimately mixed nature of the finely divided solids and water.

The process of this invention may be illustrated in the followingexamples:

EXAMPLE I for COMPARISON Bromochlorodimethylhydantoin

Water (7500 lbs.) and then dimethylhydantoin (1700 lbs.) were charged toa 2000 gallon reactor. Bromine (1061 lbs.) and sodium hydroxide (1,327lbs. of 20% aqueous solution) were added at such a rate that 25° C.temperature was not exceeded. The pH was controlled at 6.8 to 7.0. Afterthe bromine addition was completed, chlorine (1413 lbs.) and sodiumhydroxide (3,986 lb. of 20% aqueous solution) was added at such a rateto again control the pH at 6.8 to 7.0 and the temperature at 25° C. Theresultant slurry of solids containing bromochlorodimethylhydantoin wasfiltered, washed with water, and extruded or shaped in tablet, thendried.

EXAMPLE II Bromochlorodimethylhydantoin - Preferred Method

In accordance with the preferred method of preparing ofbromochlorodimethylhydantoin, water (7500 lbs.) and thendimethylhydantoin (1700 lbs.) were charged to a 2000 gallon reactor.Bromine (1061 lbs.) and an aqueous slurry of 246 lbs. of calciumhydroxide were added at such a rate that 25° C. temperature was notexceeded. The pH was controlled at 6.8 to 7.0. After the bromineaddition was completed, chlorine (1413 lbs.) and calcium hydroxide(aqueous slurry, 738 lbs.) were added at a rate to again control the pHat 6.8 to 7.0 and temperature at 25° C. The resultant slurry of solidswas filtered but not washed. By-product calcium chloride was thusretained by the solid product. The product thus produced was thendensified into the desired tablet shapes and dried to the desiredproportion of water and calcium chloride.

The crush strengths of bromochlorodimethylhydantoin prepared fromExamples I and II were compared after densification into representativeforms. The results of these tests, which are summarized in Table Ibelow, show that halogenated hydantoins synthesized and densified inthis fashion yield reproducibly higher crush strengths than thosesynthesized by other means.

Application of the preferred method of the present invention to thepreparation of other dihalodimethylhydantoin is illustrated in ExamplesIII and IV.

EXAMPLE III Dibromodimethylhydantoin

Water (7500 lbs.) and then dimethylhydantoin (1700 lbs.) were charged toa 2000 gallon reactor. Bromine (2122 lbs.) and an aqueous slurry of 492lbs. of calcium hydroxide was added at such a rate that 25° C.temperature was not exceeded, while controlling the pH at 6.8 to 7.0.Chlorine (942 lbs.) was then injected into the reaction mixture tocomplete the bromination, during which time an aqueous slurry of calciumhydroxide (492 lbs.) was added. The temperature was not permitted toexceed 25° C. and the pH was monitored between 6.8 and 7.0. Theresultant slurry of solids containing dibromodimethylhydantoin wasfiltered but not washed, leaving residual by-product calcium chloride inthe product. The product was then densified into the desired shapes anddried to the desired proportion of water and calcium chloride.

EXAMPLE IV Dichlorodimethylhydantoin

Water (7500 lbs.) and then dimethylhydantoin (1700 lbs.) were charged toa 2000 gallon reactor. Chlorine (1883 lbs.) and an aqueous slurry of 984lbs. of calcium hydroxide were added at such a rate that 25° C.temperature was not exceeded, while maintaining the pH at 6.8 to 7.0.The resultant slurry of solids containing dichlorodimethylhydantoin wasfiltered but not washed, leaving behind the by-product calcium chloridein the product. The product was then densified into the desired shapesand dried to the desired proportion of water and calcium chloride.

EXAMPLE V Bromochlorodimethylhydantoin Mechanically Mixed with CalciumChloride and/or Water for Densification

The bromochlorodimethylhydantoin prepared as in Example I for Comparisonwas mechanically mixed with varying amounts of water and calciumchloride, and the resultant particulate solids were then either extrudedor compressed into tablets. Crush strenghts for such tablets containing2.0-5.0% water and 3.0-6.0% calcium chloride by weight were measured andare reported in Table I.

From Table I it can be seen that densified halogenated dimethylhydantoins prepared by this method and containing water or calciumchloride alone (Samples II, III) exhibit lower crush strengths thanthose containing mixtures of calcium chloride and water (Samples IV-VI,VIII).

From Table I it can also be seen that densified shapes of thehalogenated dimethylhydantoin prepared as described in Example II wereof consistently superior strength than densified shapes of the purecompound prepared as described in Example I for Comparison. Whendensified without additives (Sample I), the shapes had the lowest crushstrengths.

When the halogenated dimethylhydantoin was mechanically mixed with waterand calcium chloride the densified sample had crush strengths in therange of 60-114 pounds (Samples IV, V). Halogenated dimethylhydantoinsprepared by the preferred method (Examples II-IV) and then densifiedexhibited the highest crush strengths in the range of 115-240 pounds(Sample V, tablets).

Extrusions of the halogenated dimethylhydantoins exhibited similarcharacteristics, and had crush strengths in the range of 41-51 lbs.(Sample VIII) when prepared by the preferred method (Example II), buthad crush strengths of only 22-30 lbs. (Sample VII) when prepared byExample I for Comparison.

Thus, halogenated hydantoins containing calcium chloride and water aresignificant improvements over the conventional prior art material(Sample I), with the preferred in situ formed mixtures (Samples VI andVIII) representing the most desirable product.

                                      TABLE I                                     __________________________________________________________________________    Sample/                 Densification                                                                         Crush                                         Preparation Method/Additives*                                                                         Product Strength                                      __________________________________________________________________________    I.  Bromochlorodimethylhydantoin pre-                                                                 Tablets -                                                                              8-24 lbs.                                        pared as described in Example I;                                                                  11/8"                                                     nothing added.      diameter**                                            II. Bromochlorodimethylhydantoin pre-                                                                 Tablets -                                                                             20-29 lbs.                                        pared as described in Example V;                                                                  11/8"***                                                  water (.5-5%) added, mechanically                                             mixed.                                                                    III.                                                                              Bromochlorodimethylhydantoin pre-                                                                 Tablets -                                                                              0-39 lbs.                                        pared as described in Example V;                                                                  11/8"***                                                  calcium chloride (1.5-10%) added,                                             mechanically mixed.                                                       IV. Bromochlorodimethylhydantoin pre-                                                                 Tablets -                                                                             60-74 lbs.                                        pared as described in Example V;                                                                  11/8"***                                                  water (1.3%); calcium chloride                                                (2.0%) added, mechanically mixed.                                         V.  Bromochlorodimethylhydantoin pre-                                                                 Tablets -                                                                              75-114 lbs.                                      pared as described in Example V;                                                                  11/8"***                                                  water (2.6%); calcium chloride                                                (4.0%) added, mechanically mixed.                                         VI. Bromochlorodimethylhydantoin, water                                                               Tablets -                                                                             115-240 lbs.                                      (2.0-5.0%) and calcium chloride                                                                   11/8"***                                                  (3.0-6.0%) prepared, in situ, as                                              described in Example II.                                                  VII.                                                                              Bromochlorodimethylhydantoin pre-                                                                 Extrusion                                                                             22-30 lbs.                                        pared as described in Example I;                                                                  5" × 3/4"                                           nothing added.                                                            VIII.                                                                             Bromochlorodimethylhydantoin, water                                                               Extrusion                                                                             41-51 lbs.                                        (2.0%) and calcium chloride (3.0%)                                                                5" × 3/4"                                           prepared, in situ, as described in                                            Example II.                                                               __________________________________________________________________________     *All percent compositions are given as weight percents.                       **Compressed to 75-85% of product's true density.                             ***Compressed to various levels of densification.                        

I claim:
 1. A densified halogenated hydantoin composition comprising:ahalogenated dimethylhydantoin; about 1-5% water by weight of thecomposition; and about 2-6% calcium chloride by weight of thecomposition.
 2. A composition, as claimed in claim 1, wherein thehalogenated dimethylhydantoin is a member selected from the groupconsisting of:dibromodimethylhydantoin; dichlorodimethylhydantoin;bromochlorodimethylhydantoin; and mixtures thereof.
 3. A composition, asclaimed in claim 2, wherein the member is bromochlorodimethylhydantoin.4. A method for producing densified halogenated hydantoin compositionscomprising the steps of mechanically mixing a halogenateddimethylhydantoin with about 2-6% calcium chloride by weight of thecomposition and about 1-5% water by weight of the composition andthereafter densifying the resulting mixture.
 5. A method, as claimed inclaim 4 wherein the halogenated dimethylhydantoin is a member selectedfrom the group consisting of:dibromodimethylhydantoin;dichlorodimethylhydantoin; bromochlorodimethylhydantoin; and mixturesthereof.
 6. A method, as claimed in claim 5, wherein the member isbromochlorodimethylhydantoin.